Near-field communication (NFC) is a short-range wireless communication technology for exchanging data between devices over distances of centimeters to tens of centimeters, generally up to 10 cm. One example application for NFC is radio-frequency identification (RFID) where a reader device can detect and retrieve data from a tag equipped with an antenna.
Generally, a first device enters a polling mode where it generates an electromagnetic field in order to poll for other available NFC devices in the vicinity. These close NFC devices should answer to let the first device know about them. In some cases, the close devices answer by only modulating the carrier electromagnetic field, the modulation data forming a signal which can be demodulated by the first device.
On this principle, the ISO (International Standards Organization) and the NFC-Forum have defined more refined protocols and mechanisms enabling devices of various manufacturers to interoperate. More precisely, the standards define several technologies to cover different manufactures and legacy technologies, namely the NFC-A, NFC-B and NFC-F technologies. Each technology is associated with a group of transmission parameters defining a complete communication protocol, like, for instance: bit rate, modulation scheme, bit level coding, frame format etc. However, all the technologies share a few core parameters enabling a basic interoperating, e.g. the same radio-frequency for the carrier electromagnetic field (13.56 MHz), same protocol, and same command set.
The FIG. 1 shows a basic protocol exchange between two devices according to the NFC-F technology.
A first device D1 is in a so-called “poll mode” which can be considered as the initial mode for a device trying to discover its neighborhood by generating a carrier field. It sends a poll frame PF, which can be received by NFC-complaint devices in the vicinity.
A device D2 is in listen mode. This listen mode can be considered as another initial mode for a NFC device, wherein it does not generate any carrier field but is continuously listening for the electromagnetic carrier field generated by another device. When it detects the field generated by the device D1 and receives the poll frame PF, it answers with a Listen Frame LF so as this frame can be perceived by the device D1.
This Listen Frame enables the device D2 to let the first device D1 know about its presence and which mode of communication is possible.
There are two modes of Near-Field Communication:                a passive communication mode where the device D2 (i.e. the one which has not already generated a carrier field) will send messages by using the carrier field of D1 only.        An active communication mode, where the device D2 can generate its own carrier field to send its messages. In such a mode (also called “peer-to-peer mode”) both devices alternatively generate a carrier field to communicate.        
The passive communication mode is used when the receiving device D2 is a tag, e.g. a Type 3 Tag (T3T) according to the NFC Forum Digital Protocol specification.
The active communication mode can be used when the receiving device D2 is a more complex device, having means to generate its own carrier field, and generally means to embed software applications. Such devices can be mobile phones, like smartphones, tablets, laptop computers, etc.
Such device D2 may also emulate a simple tag and therefore interoperate with the first device D1 in a passive communication mode.
There is a need for taking into consideration the situation of advanced communication devices which can emulate NFC devices. In particular, there is a need to propose solutions, especially an architecture, for a communication device to emulate several NFC devices and to let other parties know about these emulated devices.